Migrant caravan: California considers suing Trump administration over tear gas incident on Mexico border

States have limited power over federal-controlled borders unless a state resident was affected

California is considering taking legal action against Donald Trump’s administration over the use of tear gas on migrants at the US-Mexico border.

“We have been approached by folks who have expressed complaints...We are monitoring what’s occurring.” California Attorney General Xavier Becerra told Reuters.

US border agents used the substance to disperse a crowd of mostly Central Americans, including children, trying to illegally entering the country at the San Ysidro port near San Diego, California.

The state has limited power over the federally-managed port but if a California resident was adversely affected by the tear gas use then they may have cause to take legal action.

“I can’t act unless the rules are on our side,” Mr Becerra said.

The tear gas incident prompted criticism of the administration, and particularly, Mr Trump's stance towards the migrant caravan of approximately 5,000 people camped out at a sports complex in Tijuana, Mexico.

Many are seeking asylum in the US as they are fleeing the rampant gang violence in their native Honduras, Guatemala, and El Salvador.

US border agents have been processing approximately 40 to 100 asylum applications a day at the San Ysidro port, leaving migrants with murky timelines on how long they will have to wait in Mexico.

The frustration came to a head on 25 November when hundreds of migrants attempted to storm the border barriers, apparently overwhelming the border patrol.

Tear gas and pepper spray were used and Trump administration officials have justified its use multiple times. Department of Homeland Security Secretary Kirstjen Nielsen called the incident "entirely predictable. This caravan, unlike previous caravans, had already entered Mexico violently and attacked border police in two other countries. I refuse to believe that anyone honestly maintains that attacking law enforcement with rocks and projectiles is acceptable."

Ms Nielsen also wrote that "90 per cent" of the migrants are not eligible for asylum in the US.

Per US Citizenship and Immigration Services, asylum seekers must "demonstrate [they] have suffered persecution or fear that they will suffer persecution due to" five factors: race, religion, nationality, membership in a particular social group, or political opinion.

Mr Trump himself has said the use of force was "very safe" and necessary in order to protect the border from the caravan, which he has called and "invasion" of "criminals" and accused of travelling with "unknown Middle Easterners" for several weeks.

He also demanded on Twitter Mexico should take more responsibility for the crisis. Following the incident he tweeted: "Mexico should move the flag waving Migrants, many of whom are stone cold criminals, back to their countries. Do it by plane, do it by bus, do it anyway you want, but they are NOT coming into the U.S.A. We will close the Border permanently if need be. Congress, fund the WALL!"

The United Nations and Democratic members of Congress have slammed the administration after photographs and reports of children fleeing the tear gas were published.

Some experts have cited language in the UN charter, which states members “shall refrain in their international relations from the threat or use of force against the territorial integrity” of other countries.

The Ninth Circuit federal district court in California had earlier blocked Mr Trump's executive order attempting to change US policies for seeking asylum. The administration is challenging the ruling and has floated the idea of giving migrant families who are seeking asylum 20 days to make the choice between staying in detention with their children until deportation hearing or letting their children be kept in a separate facility so relatives already in the US can come claim custody of them.

Mr Trump is also continuing to push Congress to fund his border wall project, running along the 2,000-mile international line with Mexico.